Latch structure



Feb. 2, 1960 vE. w. BAGNELL ET AL 2,923,562

LATCH STRUCTURE Filed Aug. 2, 1955 ,cfa-2 /c/G -3 United States Patent O LATCH STRUCTURE Edgar W. Bagnell, Glendale, and William K. Ansite,

Application August 2, 1955, Serial No. 526,012

1 Claim. (Cl. 285-143) This application relates to a novel latch assembly for use with a telescoping tubular member; for example, the logging sub shown in the application to Montgomery et al., entitled Logging Sub, Serial No. 458,413, tiled September 27, 1954, now Patent No. 2,726,848.

The Montgomery et al. patent cited above shows a logging sub adapted to be inserted in a drill string, wherein the sub may be latched in collapsed relation to transmit torque to a bit, and wherein the latch may be released to' permit extension of the sub to uncover suitable openings through which caliper arms-may be extended to caliper the well bore diameter as the drill string is withdrawn therefrom.

It is the `principal object of this inventiontoprovide a novel form of latch assembly fo'r use in a telescoping sub such as set forth above. 7. ,A

A further object ofthe invention is to provide a latch for releasably latching a telescoping sub in collapsed relation,`wherein thelatch may be reset if it should be inadvertently tripped or if it is desired to remove the tool and resume drilling. K

The preferred form of our invention is described in the following detailed specification, and illustrated by way of example in the accompanying drawings, wherein:

Fig. 1 shows a longitudinal section of .a telescoping sub embodying the principles of the invention.

Fig. 2 is a fragmentary sectional view o'f a portion of Fig. 1 drawn to an enlarged scale and illustrating the latch 'in its latched relation.

Fig. 3 is a view similar to that shown in Fig. 2, and illustrates the latch in its released position and the sub partially extended.

Figs. 4 and 5 are enlarged views of the ball engaging portions illustrated in Figs. 2 and 3, in latched and unlatched positions, respectively.

Referring now to the drawings wherein similar reference numerals are used to denote the same elements throughout the various views sho'wn, and referring more particularly to Fig. l thereof, 10 generally indicates a telescoping sub embodying the principles of the invention.

The sub 10 is composed of an outer tubular member 11 and an inner tubular member 12 slidable therein. The outer tubular member 11- comprises an upper section 13 and a lo'wer section 14. The inner tubular member 12 comprises an upper head section 15, an intermediate section 16, and a lower section 17. The upper end of the outer tubular member 11 is provided with a threaded pin 18 adapted to be connected to the lower end of a drill string (not shown). The lower end of the inner tubular member 12 is provided with a box 19 adapted to' be connected to a bit (not shown). e

The lower end of the lower section 14 of the outer tubular member 11 is provided with depending fingers 20, which intermesh with corresponding grooves 21 formed in the lower sectio'n 17 of the inner tubular member 12 to prevent relative rotation therebetween when the sub 10 is in its collapsed relation. The meeting surfaces 22 audV 23 of the outer member section 14 and the inner 2,923,562 y Patented Feb. 2, 1960 Fice member section 17, respectively, are tapered downwardly and outwardly, and the lower inner corner of each of the finger 20 is chamfered, as shown at 24, for purposes which will hereinafter be described. Y

The upper annular shoulder of the lower section 14 of the outer member 11 is formed with an annular arcuate depression 25 at its inner edge.V A plurality of locking balls 26 are mounted in suitable lateral bores 27 in the walls of the lower section 17 of the inner member 12, and have a diameter d greater than the thickness of the section wall to project outwardly therefrom a distance d1 and seat in the arcuate depression 25 to latch the two members 11 and 12 in their collapsed or contracted relation. The balls 26 are retained in their Yextended or latching position by a locking sleeve 28 slidably received within the section 17 of the inner member 12, the outer peripheryof said sleeve maintaining the balls engaged with the arcuate seat 25. The sleeve 28 is provided with a irst annular groove 29 relieved from the periphery a depth dzat least as great as the projection d1 o'f the balls and into whichthey balls 26 arereceived to permit eX- tension of'the sub 10 when the sleeve 28 is moved downwardly relative to the inner member 12. The sleeve 28 is normally held in its uppermost position by a spring 30 confined between the lower end thereof and an upwardly facing shoulder 32 formed in the section 17 of the inner-tubular member/12.V The upper` end ofthe sleeve 28 isformed with a downwardlyand inwardly tapered shoulder 33 Vadaptedto beengaged by a suitable shoulder on a well toolv lowered or Vdropped within the well string. p l v In order'to permit relatching of the subafter the tool has been withdrawn, a second setof balls 34 is mounted in suitable bores35 in the section 17 above the balls 26. These balls cooperate with an annular groove 36 formed in the sleeve 28. The groove 36 has a downwardly and outwardly inclined lo'wer wall 37 spaced a distance above lower wall 38 of groove 29 less than the center-to-center spacing of the .upper and lower balls 34, 26. T he width of the grooves 36, 29 is suchthat bothrthe balls 26, 34 can be accommodated atthe sameY timerto the. Vdepth, d1 when alined with the corresponding grooves.

Referring specifically to'Figs. 4 and 5, the balls 34 are seen to have their centerline slightly above lower edge wall 37 of groove 36 when sleeve 28 is returned to its upper position. Hence, when balls 34 are forced inwardly, as by chamfer 24 of fingers 20, the sleeve 28 is cammed downwardly to receive the balls 34 in upper groove 36. Such downward camming displaces the lower edge wall 38 of lower gro'ove 29 downwardly from a position slightly above the centerline of balls 26 to a position slightly below such centerline. Accordingly, the lower groove 29 is thus positioned to receive balls 26 when these in turn are cammed inwardly by chamfer 24.

In the use of the device, the elements are assembled in the relationship Ashown in Fig. l and the device is inserted in a well string. When it is desired to' extend the sub, a tool is lowered or dropped through the vwell string and seats in the shoulder 33, thus forcing the sleeve 28 downwardly until the annular groove 29 is in register with the balls 26. The balls 26 then move inwardly and permit the extension of the sub.

The sub may be relatched after the unlatching tool is withdrawn and the sleeve 28 is inl its uppermost position by lo'wering the outer member 11 onto the inner member 12. The chamfer 24 on the lower end of the lingers 20, or the tapered surface 23, will contact the balls 34. forcing them inwardly. The lower edge of the inclined wall 37 of the groove 36 is below the centerline of the balls 34 and thus the inward movement of the balls 34 in cooperation with the inclined wall 37 of the groove 36 forces the sleeve downwardly until the lower edge of the causing the sleeve ZSftomov downwardly slightlylfuri ther, lin Yorder toaccommodate the balls 26fwithin` the groove 29.- ,When the sub, reaches'itsfully closedposition, as ,illustrated in Fig. 2,the spring 30 forces the sleeve upwardly, moving the locking `balls 26 into seating engagement with the arcuate recesses l2S.` Sincethelower edge of theinclined surface 38 is no'w above the `center line of balls` 26, the` balls 26 are prevented from rfc-entering the gr`oovef29. t

From the foregoing description it maybe-seen that we have provided a very simple,` ecient latch structure for holding 'two tubular members `.in telescoped relation wherein the latch may be released or reltched as desired.

While we have shown-and described thepreferred form ofthe inventio'n, itis obvious that various' changes may be made in -vits construction by those-skilled in the art, without` departing from the spirit of theinvention as dened in the appended claim.

t Havingthus described our invention, what-,we claim and desire tosecure by Letters Patent is:

`In a well tool for endwise threaded connection in a string of pipe, `the combination comprising an outer tubular member. having an enlarged bore portion', intermediate its ends, an inner longitudinally slotted ,tubular member extending slidably and rotatably intoy saidouter v a lateral bore of said inner member and positioned along Vsaid inner member to engage an arcuate seat in said an- 'upper annular 4shoulder sized for engagement by a tool Y lowered through'said pipe string whereby said sleeve may be moved'to its lower unlocking position, said tirst gro'ove being opposite said rst ball-in said unlocking position and sized to receive said first ball out of engagement with said seat, and a second ball retained partially within a lateral bore of said inner member and spaced above said first ball for reception in said second groove in said unlocking` position, whereby said inner member` may be moved to its `extended rotatable position when said sleeve is in its unlocking position,` said second groove having its lower edge-spaced below the center line of saidsecond ball in said locking po'sition a `distance such that` inward displacement of' said second ball upon downward movement of the lower end of said outer member from said extended position cams said lower edge downwardly as said second ball is received in said second groove, said first gro'ove having its lower edge spaced above the center line of'said first ball in said locking position and displaced below such-center line when said second ball is received in said second groove, whereby Ythe lower end `of said outer member may/successively displace said second ball into said second groove and said rsttball intosaid rst groove assaid members are moved into their contracted position.

References'Cited in the tile of this patent UNITED STATES PATENTS 

